Androgen receptors in human melanoma cell lines IIB-MEL-LES and IIB-MEL-IAN and in human melanoma metastases

The presence and characteristics of androgen receptors (ARs) have been described by our group in one human melanoma cell line. We have now investigated their presence in two other human melanoma cell lines, IIB-MEL-LES and IIB-MEL-IAN, as well as in biopsies from human metastatic melanoma. Scatchard analysis revealed a single binding component for both cell lines, the apparent dissociation constant obtained being 15 nM, with a binding capacity of 280 fmol/mg total cell protein, for IIB-MEL-LES cells and 14 nM, with a binding capacity of 206 fmol/mg total cell protein for IIB-MEL-IAN cells. When specificity was assessed, not only androgen and anti-androgen but also non-androgenic compounds were able to compete for [3H]R1881 binding, as seen before. When immunocytochemistry of IIB-MEL-LES and IIB-MEL-IAN cells was performed for ARs, both cell lines were deeply stained in the nucleus, whereas no staining was found for oestrogen or progesterone receptors. Every specimen of melanoma metastases tested for the presence of ARs was deeply stained, and in the majority the intensity of the staining was high. Several hormones and anti-hormones were tested for their ability to affect cell proliferation. In both cell lines, testosterone, dihydrotesterone, oestradiol and progesterone significantly stimulated cell proliferation, and this was reversed by hydroxyflutamide, bicalutamide or tamoxifen.